Create per-CPU mutex for XSCOM usage.

Change-Id: I76ad5c1d553d544b52910afd82e2716781ea13b9
Reviewed-on: http://gfw160.austin.ibm.com:8080/gerrit/140
Tested-by: Jenkins Server
Reviewed-by: Thi N. Tran <thi@us.ibm.com>
Reviewed-by: Douglas R. Gilbert <dgilbert@us.ibm.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/src/include/sys/mmio.h b/src/include/sys/mmio.h
index eb146da72..c36a13821 100644
--- a/src/include/sys/mmio.h
+++ b/src/include/sys/mmio.h
@@ -2,6 +2,7 @@
 #define __SYS_MMIO_H
 
 #include <stdint.h>
+#include <sys/mutex.h>
 
 #ifdef __cplusplus
 extern "C"
@@ -25,6 +26,20 @@ uint64_t mmio_hmer_read();
  */
 int mmio_hmer_write(uint64_t value);
 
+/** @fn mmio_xscom_mutex()
+ *  @brief Returns the per-CPU mutex for the XSCOM hardware logic.
+ *
+ *  @pre Task must be pinned to a CPU by task_affinity_pin.  Function will
+ *       assert if not met.
+ *
+ *  @returns The existing mutex for the CPU or creates a new one.
+ *
+ *  @note The task should only interact with the mutex while protected by an
+ *        affinity pin.  If the pin is moved the mutex is no longer
+ *        guarenteed for the CPU the task is executing on.
+ */
+mutex_t mmio_xscom_mutex();
+
 #ifdef __cplusplus
 }
 #endif